Tanning substance for tanning animal hides and process of preparing the same



PATENT @FFHCCE.

OSCAR LOW-BEER, OF FRANKFORT-ON-THE-MAIN, GERMANY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE CHEMICAL FOUNDATION, INC., A CORPORATION OF DELA- WARE.

TANNING SU'IBSTANCE FOR TANNING ANIMAL 'HIDES AND PROCESS OF THE SAME.

IALQL'NML Specification of Letters Patent.

No Drawing.

July 20. 1916. Aug. 17, 1916, and Aug. 24,

1916), of which the following-is a specification.

Hitherto there were used for the preparation of artificial tanning materials only homogeneous aromatic compounds such for instance as phenoland cresol sulfonic acids, naphthelenesulfonic acids, naphtholsulfonic acids. naphthylaminesulfonic acids and the like, by combining in a suitable way the individual bodies or their isomeric mixtures.

In the course of my experiments in this art I have made the observation that by coupling compounds of various classes of bodies of the general formula:

wherein X stands for an aliphatic residue or an aromatic residue, Y for a different residue, asfor instance another aliphatic residue. another aromatic residue, a vegetabletanning substance or the like, and wherein Z means a connecting link, an atom or an atomic group: tanning substances are obtained the molecules of which are com posed of the most different kinds of components. A great number of new tanning substances can be produced by these processes which possess certain advantages over those hitherto known. For instance naphtheleneor anthracene-sulfonic acids, which when combined alone with a diazo compound do not react. can be used. after being combined 'with components capable of being coupled. for tannin'g purposes and united so as to form coloring matters directly on the hide.

ningsubstances or other admixtures. and

also when used for the combined tanning PREPARING- lPatented uly 4t, 1922..

Application filed August 2, 1918. Serial No. 248,066.

processes wherein both vegetable and mineral tanning substances are employed.

Examples.

1. 32 kilos of tannin and 51 kilos of barium cresolsulfonate are treated on the water bath for about 4 hours with 30 kilos of a formaldehyde solution of 30 per cent strength. After acidifying with hydrochloric acid the glue solution is precipitated by the condensation productwith a reddishwhite color. The dry substance gets charred when heated without previously melting; it is soluble in water and alcohol but insoluble in ether and benzene.

2. 32 kilos of tannin and 42 kilos of naphthalenesulfonic acid are carefully condensed at water-bath temperature with 20 kilos of a formaldehyde solution of 30 per cent strength and the condensation product is further treated as indicated in Example 1. The original solution shows on litmus paper an acid reaction and precipitates glue lose, waste liquor from sulfite cellulose, etc.

In German Patent No. 281484 there is described a process according to which aromatic compounds containing 'a hydroxyl group are coupled with glycerine and sulfuric acid, whereas in Austrian Patents Nos. 69375 and 69376 as well as in British Patent No. 18258/1913 are described processes according to which certain kinds of sugar are 1 to be used as coupling agents for phenols. However. in these processes the aliphatic compounds only serve as means for coupling identical components consisting of aromatic bodies containing a hydroxyl group in which cases at least two of such aromatic nuclei are coupled by an aliphatic compound. Contrary to this. the examples hereinbefore given show that in the different processes of my present invention heteroand the whole is condensed with 100 kilosgeneous components, consisting of aliphatic and aromatic compounds, are coupled together, whereby a number of hitherto unknown tanning substances can be produced which are distinguished from others by their excellent solubility in water and the easy way in which they can be prepared.

The last mentioned new products precipitate animal glue and possess the same properties as the hereinbefore described products.

Examples.

3. 94 kilos of phenol are sulfonated with 98 kilos of sulfuric acid of 98 per cent strength at water-bath temperature, whereupon 92 kilos of glycerine are introduced of a formaldehyde solution of 30 per cent strength. The mass thus obtained is diluted with water, filtered and neutralized with an alkali until there is but a slightly acid reaction. The solution may be directly used as tanning liquor or it may be completely neu tralized and evaporated to dryness. The dry substance gets charred when heated while strongly pufiing up without first melting; it is very readily soluble in water but insoluble in ether and benzene. The aqueous original solution shows on litmus and Congo paper an acid reaction and precipitates glue with a yellowish color; the addition of an acid or an alkali does not cause any separations.

4. Into 23 kilos of 2-6-naphtholsulfonic acid are introduced 18 kilos of glucose dissolved in 10 litres of water and this mixture is caused to react at water bath temperature with 10 kilos of a formaldehyde solution of 30 per cent strength. The product is dissolved in hot water. Thesolution thus obtained does not precipitate glue in a neutral state, however on acidifying it with sulfuric acid it precipitates glue with a reddish coloration. The dry substance obtained by evaporation gets charred when heated without melting; it is very readily soluble in water, but insoluble in ether and benzene.

5. 15 kilos of cresolsulfonic acid are heated on the water bath for 4 hours with 5 kilos of glucose and 8 kilos of 2. formaldehyde solution of 30 per cent strength. The reac tion mass is diluted with hot water and fil tered. The solution shows on litmus or C ngo paper an acid reaction and precipitates glue with a brownish color. Thedry substance gets charred when heated with outmelting it; it is readily soluble in water but insoluble in ether and benzene.

6. 25 kilos of cresolsulfonic acid are heated on the water bath for 4 hours with 5 kilos water and filtered. The filtrate precipitates animal glue and shows on litmus or'Congo paper an acid reaction. The dry substance is readily soluble in water, insoluble in ether and benzene; when heated it gets charred without melting previously.

7. 25 kilos of sodium 1-5-naphthylaminsulfonate are heated on the water bath for 6 hours with "20 kilos of glucoseand 10 kilos of a formaldehyde solution of 30 per cent strength; there is then added some water and the whole filtered.- The solution shows on litmus paper a slightly. alkaline reaction and after being acidified with diluted acetic acid it precipitates glue. The dry substance is readily soluble in water but insoluble in ether and benzene.

8. 26 kilos of naththalenesulfonic acid are coupled at water bath temperature with 20 kilos of glucose and 10 kilos of a formaldehyde solution of 30 per cent strength whereupon hot water is added and the whole filtered. The filtrate shows on litmus and Congo'paper an acid reaction and precipitates glue with a brownish color. The dry substance when heated burns with a soot producing flame without melting; it is readily soluble in water, insoluble in ether and benzene.

9. 100 kilos of coal tar phenols of boiling point 185200 are mixed with 275 kilos of crystallized sodium sulfite, 275 litres of wa ter and 150 kilos of a formaldehyde solution of 30 per cent strength and this mixture is heated in an autoclave at 140150 C. until a test sample after being acidified with a glue solution shows no further increase of the precipitate. The condensation mass is slightly acidified with sulfurica-cid and the sulfurous acid is boiled ofi. There are then added 25 kilos of glucose and 75 kilos of a formaldehyde solution of 30 per cent strength and the whole is condensed at water bath temperature for another 6 hours. Into the reaction mixture hot water is added and the whole filtered. The solution shows on litmus or Congo paper an acid reaction and precipitates glue with a brownish color. The dry substance is very readily soluble in water, insoluble in ether and benzene.

10. 18 kilos of p-dioxydiphenyl are condensed by heating on the water bath with 38- kilos of cresolsulfonic' acid and 20 kilos of a formaldehyde solution of 30 per cent strength. The mass thus obtained is diluted with 150 litres ofhot water, neutralized with caustic soda lye and after addition of 50 kilos of crystallized sodium sulfite heated in an autoclave for 8 hoursat 140-150 C. The product obtained is filtered, slightly acidified and the sulfurous acid boiled off.

11. 10 kilos of p-dioxydiphenylmethan are sulfonated with 5 kilos of sulfuric acid of 98 per cent strength, whereupon 11 kilos of 1-5-naththylaminsulfonic' acid are introduced and the whole is heated with 7 kilos of phosphorus pentoxide for 4 to hour to about 150 C. The mass thus obtained is diluted with hot water and filtered.

The tanning with the herein described new tanning substances is carried out, according to the kind of skins, either in the tan pit, in the reel or in the fulling trough, whilst the strength of the liquor is accordingly adjusted and the duration of the tanning operation modified. The new tanning substances may be used immediately either alone or mixed with other tanning agents or some of the usual additional substances and they are also adapted for the combined tanning processes whereinbotli vegetable and mineral tanning substances are employed.

It is, of course, to be understood that throughout the specification and claims the various salts of the acids referred to, which salts are preferably in acid solution, are to be considered equivalents of the acids per se. It is furthermore to be understood that my invention is not to be limited to the particular embodiments thereof herein described for purposes of illustration only.

Having now described my invention, what I claim is:

1. The process for the preparation of a tanning material which comprises heating 1 hydroxyl derivative of a hydrocarbon, which derivative contains three or more carbon atoms and more than one hydroxyl group, an aromatic compound containing a sulfonic acid group and formaldehyde.

2. The process for the preparation of a tanning material which comprises heating a mixture containing a carbohydrate, an aromatic compound containing a sulfonic acid" group and formaldehyde.

3. The process for the preparation of a tanning material which comprises, heating a mixture containing a carbohydrate, a naphthol sulfonic acid and formaldehyde.

4:. The process for the preparation of a tanning material which comprises heating a mixture containing a carbohydrate, 2-6 naphthol sulfonic acid and formaldehyde.

5. The process for the preparation of a tanning material which comprises heating a mixture containing a carbohydrate, 2-6 naphthol sulfonic acid and formaldehyde to a temperature of about 90 C.

6. The process for the preparation of a tanning material which comprises heating a mixture containing glucose an aromatic compound containing a sulfonic acid group and formaldehyde.

7. The process for the preparation of a tanning material which comprises heating glucose, a naphthol sulfonic acid and formaldehyde.

8. The process for the preparation of a tanning material which comprises treating glucose with 2-6 naphthol sulfonic acid in the presence of formaldehyde at a temperature of about 90 C.

9. The process for the preparation of a tanning material which comprises treating about 23 parts of a naphthol sulfonic acid and about 18 parts of glucose with about 10 parts formaldehyde at a temperature below 100 C.

10. The process for the preparation of a tanning material which comprises treating about 23 parts of2-6 naphthol sulfonic acid and about 18 parts of glucose with about 10 parts formaldehyde at a temperature of about C.

l1. A tanning material consisting of an amorphous powder, said material containing a sulfonic acid group soluble in water and alkali, insoluble in ether or benzene. charring when heated at a temperature below its melting point, and capable of precipitating glue in animal tissues, and obtained by treating a hydroxyl derivative of a hydrocarbon containing more than three carbon atoms and more than one hydroxyl group with an aromatic sulfonic acid in the presence of formaldehyde at a temperature of about 90 C.

12. A tanning material consisting of an amorphous powder, said material containing a sulfonic acid group soluble in water and alkali, insoluble in ether or benzene. charring when heated at a temperature below its melting point, and capable of precipitating glue in animal tissues, and obtained by treating glucosewith 2-6 naphthol sulfonic acid in the presence of formaldehyde at a temperature of about 90 C.

In testimony whereof I afiix my signature in the presence of two witnesses.

DR. OSCAR LOW-BEER. Witnesses:

CARL HEYDORN, GEORGE KASBURN'. 

